Keyboard musical instrument



Jan. 18, 1966 KUNlMlTsu MIZOBE 3,229,560

KEYBOARD MUS I CAL INSTRUMENT Filed Feb. 15, 1965 4 Sheets-Sheet 2 F l G. 5

Jan. 18, 1966 KUNlMlTSU MIZOBE 3,229,560

KEYBOARD MUSICAL INSTRUMENT Filed Feb. 15, 1965 4 Sheets-Sheet z United States Patent 3,229,560 KEYBOARD MUSICAL INSTRUMENT Kunimitsu Mizobe, 1314 Nukui-machi, Nerima-ku, Tokyo-to, Japan Filed Feb. 15, 1965, Ser. No. 432,568 Claims priority, application Japan, Apr. 14, 1964, 39/2tl,930, 39/20,931; Aug. 7, 1964, 39/44,:342 4 Claims. (Cl. 84-451) has been studied a problem of providing such an instrument, but the just intoned keyboard musical instrument has not been heretofore realized for practical use, since complete theories were not established in the science of musical engineering. Equally tempered keyboard musical instruments known heretofore are convenient musical instruments, but harmonies produced thereby are unpleasant, because the scale of equal temperament is an impure scale.

It is a general object of the present invention to provide a keyboard musical instrument in which a present day equally tempered keyboard musical instrument, retaining its advantageous features, is utilized as a basis, and which is made to be able to readily produce tones in the scale of just intonation through a certain slight addition to the construction.

Briefly stated, the present invention resides in a just intoned keyboard musical instrument with 12 pairs of tones, i.e. 24 tones for each octave, in which are provided 12 keys for each octave, each key producing either of the pair of tones, one of which is a first tone in a scale of equal temperament, and the other is a tone which is approximately 14 cents lower than said first tone, and there is provided switching means being freely operable by the player of the instrument to select one tone to be played, whereby one desired tone out of said pairs of tones can be produced by depressing the corresponding key.

The nature, principle, and details of the invention will become more apparent by reference to the following description taken in conjunction with the accompanying drawings in which:

FIGS. 1 through 4, 6 through 9, and 11 through 15, all inclusive, show examples of tonal arrangements on musical staffs;

FIG. is a diagram indicating a keyboard arrangement according to the invention; and

FIGS. (A) and 10(B) are schematic diagrams indicating switching arrangements.

The greatest cause of unpleasant harmony is in the impurity of the 3rd interval. FIG. 1 indicates a major scale of equal temperament for the keynote C. The intervals between C and E, F and A and G and B are all 400 cents, but the exact major 3rd, with a frequency ratio of 5:4, is approximately 386 cents. That is, the major 3rd in the scale of equal temperament is excessive by approximately 14 cents. In other words, the three tones of E, A and B are too high by approximately 14 cents. Accordingly, if these three tones are replaced by the tones which are approximately 14 cents lower as shown in FIG. 2, the harmony of the major 3rd will become pleasant. The black notes indicate the lower tones.

While the above description relates to the scale of C major, the same principle applies to any other of the major scales such as, for example G major or F major. That is,

3,229,550 Patented Jan. 18, 1966 ice pleasant harmony can be produced by lowering each of the third, sixth, and seventh tones of the scale by 14 cents.

Referring to FIG. 3 showing various major scales, there seem to be too many of different black notes, but two of them are enharmonic tones (same tones with different names). For example, D-sharp and E-flat are the same. Therefore, there are actually 12 black notes.

FIG. 4 indicates, on staffs, 12 tones in the scale of equal temperament and tones which are respectively lower by 14 cents.

Provided that these 24 tones exist in the keyboard musical instrument according to the present invention, major scales for all the key signatures are capable of producing pleasant harmonies.

The construction of the keyboard will now be described. It is not desirable to provide 24 keys in an octave. In any scale, there is no possibility of using both white and black notes for the same tone. For example, for the tone E in C major, the black is used, and the white is not, and for that in D major, white is used, and black is not. Therefore, the keyboard is constructed in the same manner as at present to have 12 keys in an octave, and white and black notes are provided for each key, one of the two notes being selected for playing by a changeover switch. The instrument can be prepared for musical performance merely by the selection of the tones required for the scale of the music and setting the corresponding switches before performance.

The relation between the keyboard and the tones is indicated in FIG. 5, wherein the capital letters designate the white notes, and the small letters the black.

It, in this keyboard musical instrument, only the white notes or only the black notes are to be used, the scale will become an ordinary scale of equal temperament same as that used conventionally. In case the player desires pleasant harmonies, he has only to interchange the necessary tones.

Chords obtained by this instrument will now be analyzed. Referring to FIG. 6, (A) is a major triad chord of equal temperament, (B) is a triad obtained from the chord (A) with its middle tone E replaced by a black note, and (C) is an absolutely perfect triad of just intonation.

The greatest disadvantage in equal temperament is in the major 3rd of 400 cents. Since the perfect 5th in the triad (B), that is, the 700 cents of CG, has an error of only 2 cents as compared with the 702 cents of the perfect 5th of just intonation, it may be permitted from the viewpoint of sensory perception. That is, the triads produced by this keyboard musical instrument are pleasant and harmonious ones which are very close to the triads of just intonation.

Next, the minor 3rd will be considered. FIG. 7 indicates a minor scale of equal temperament for the keynote C. Although each of the minor 3rds: CEb, RM), and GBb is 300 cents, a true minor 3rd, with a frequency ratio of 6:5, is approximately 316 cents. That is, since the minor 3rd in the scale of equal temperament is excessively low, its harmony can be made pleasant by increasing the interval by approximately 16 cents.

Accordingly, it is convenient if the third, sixth, and seventh tones of the minor scale can be changed for tones which are approximately 16 cents higher, as indicated in FIG. 8 showing a minor scale in which said three tones have been changed. For application to minor scales for all the key signatures, 12 square notes are necessary. FIG. 9 shows these 12 tones. Therefore, it both black notes and square notes are prepared in addition to the White notes, one octave will contain 36 tones. However, the keyboard construction is the same as that shown in FIG.

5, the only difference being that each changeover switch should be of a three-pole type.

FIG. shows changeover switches, each for use between the tone source and key for each key, two-pole and three-pole switches being shown in FIGS. 10(A) and 10(B), respectively. The tone sources are shown on musical staffs, and the changeover switches S1 and S2 are disposed between respective tone sources and keys K1 and K2.

FIG. 11 indicates analysis and comparison of minor triads. (A) represents a minor triad of equal temperament. (B) indicates the case where a square note is used.

Since the 316 cents of this minor 3rd is of just intonation, its harmony is pleasant.

However,'a minor triad may also be formed by using black notes as indicated in (C). Since the difference between (C) and (B) is only 2 cents in the 3rd intervals, they may be considered to be the same for practical purposes. That is, this means that a completely satisfactory instrument can be obtained even with only two-pole switching.

Next, the error of a perfect 5th will be considered. Since, as described in conjunction with FIG. 6, a perfect 5th is the same as the scale of equal temperament, an error of 2 cents is included. The perfect 5th of just intonation, with a frequency ratio of 3:2, is 702 cents. If it is desired to eliminate also this slight difference, that may be accomplished by tuning the white notes and black notes as indicated in FIG. 12.

With these 24 tones, it is possible to obtain perfect chords as shown in FIG. 13, in which, however, there are only two places where 700 cents are included.

In order to form the scale of a key signature, three neighboring chords are required. Therefore, if there are 15 chords, 13 scales can be for-med. The key signatures of these scales are indicated in FIG. 14.

The construction of the keyboard for this arrangement is the same as that for the aforedescribed system, that is, the same'as that shown in FIG. 5, and the method of use (selection of tones by means of changeover switches) is also the same. That is, with the same instrument, only the tuning methods are different.

FIG. 15 indicates a scale of C major-due to this system. This scale is an absolutely perfect scale of just intonation.

By the practice of the present invention as described above, it is possible to provide a just intoned keyboard musical instrument for practical use which can be easily played and, moreover, can be readily manufactured on a commercial basis.

It is to be observed that'an important feature of the just intoned keyboard musical instrument according to the invention is that it is constructed on the basis of an equally tempered keyboard musical instrument.

'What -I claim is:

1. A keyboard musical instrument comprising: a keyboard provided with 12 keys for each of a plurality of octaves; a tone source for each key 'to produce a first tone and a second tone, said first tone being a tone in a scale of equal temperament, and said second tone being a tone which is approximately 14 cents lower than said first tone; and switching means provided between each key and the corresponding tone source and adapted to select, upon being manipulated by the player of the instrument, one tone out of said first and second tones to be played by the depression of the corresponding key, whereby 24 tones are made available for playing in each octave.

2. A keyboard musical instrument comprising: a keyboard provided with 12 keys for each of a plurality of octaves; a tone source for each key to produce a first tone, a second tone, and a third tone, said first tone being a tone in a scale of equal temperament, said second tone being a tone which is 14 cents lower than said first tone, and said third tone being a tone which is approximately 16 cents higher than said first tone; and switching means provided between each key and the corresponding tone source and adapted to select, upon being manipulated by the 'player of the instrument, one tone out of said first, second, and third tones to be played by the depression of the corresponding key, whereby 36 tones are made available for playing in each octave.

3. A keyboard musical instrument as claimed in claim 1 wherein the tones are tuned as follows, in cents, from the first tone of C, for said first tones:

and for said second tones:

4. A keyboard musical instrument comprising: a keyboard including 12 keys for each of a plurality of octaves; tone source means for each key operable to produce at least two tones for each key and including a first tone constituting a tone in a scale of equal temperament and a second tone constituting a tone which is different than said first tone by an amount in cents that is uniform with respect to each key; and switching means provided between each key and the corresponding tone source means and adapted to select, upon being manipulated by the player of the instrument, one tone out of saidfirst and second tones to be played by the depression of the corresponding key, whereby at least 24 tones are made available for playing in each octave.

References Cited by the Examiner UNITED STATES PATENTS 2,097,280 10/1937 House 84-451 2,232,600 2/1941 Fickenscher 84-451 2,456,575 12/1948 Young 84-451 X 2,706,926 4/1955 Young 84-451 3,012,460 12/1961 Wilson 84451X FOREIGN PATENTS 22,884 v1 .111912 Great Britain.

LEO SMILOW, Primary Examiner. M- ER s stant Exam e 

1. A KEYBOARD MUSICAL INSTRUMENT COMPRISING: A KEY BOARD PROVIDED WITH 12 KEYS FOR EACH OF A PLURALITY OF OCTAVES; A TONE SOURCE FOR EACH KEY TO PRODUCE A FIRST TONE AND A SECOND TONE, SAID FIRST TONE BEING A TONE IN A SCALE OF EQUAL TEMPERAMENT, AND SAID SECOND TONE BEING A TONE WHICH IS APPROXIMATELY 14 CENTS LOWER THAN SAID FIRST TONE; AND SWITCHING MEANS PROVIDED BETWEEN EACH KEY AND THE CORRESPONDING TONE SOURCE AND ADAPTED TO SELECT, UPON BEING MANIPULATED BY THE PLAYER OF THE INSTRUMENT, ONE TONE OUT OF SAID FIRST AND SECOND TONES TO BE PLAYED BY THE DEPRESSION OF THE CORRESPONDING KEY, WHEREBY 24 TONES ARE MADE AVAILABLE FOR PLAYING IN EACH ACTAVE. 